Amazing Autumn on Alaska’s North Slope: Record Warmth, Record Low Sea Ice Extent

Above: The sun sets over sea ice on the Chukchi Sea near Barrow, Alaska. This archival photo was taken in spring during the OASIS (Ocean_Atmosphere_Sea Ice_Snowpack) field project. Image credit: UCAR Digital Image Library.

November 2017 averaged 17.2°F in Utqiaġvik (Barrow), Alaska, a new monthly record—besting the previous record of 15.3°F established in November 1950—and some 16.4° above average. This was also the second month of the year with a record-high average temperature, the other being this past July with a 46.0°F monthly average (the fourth highest reading observed in any month on record).

Winters in Utqiaġvik have seen a dramatic warming over the past 10 years, as Figure 1 below illustrates. In fact, it has not just been the winters. As of November 30, the average in Utqiagvik for 2017 stands at 19.5°. That value will surely drop once the upcoming cold of December is factored in, but if December temperatures are near or above average, then 2017 will still end up as the second warmest year on record in Utqiaġvik, behind only 2016 (which averaged 18.9°F). As long as this year ranks in the top eight, as seems very likely, then eight of the warmest years on record for Utqiaġvik will have occurred in just the past 11 years.

Note: Residents of Barrow voted in October 2016 to change the name of the community to Utqiaġvik, and this was made official by the state of Alaska in late 2016.

Figure 1. Average temperatures for the period November through March in Utqiaġvik (Barrow), Alaska, since 1920. The warming trend during this cold part of the year is clearly evident. Image credit: Rick Thoman, NOAA/NWS Alaska Region.

Is it possible that growth of the Utqiaġvik area has led to a significant urban heat island effect and boosted temperatures to these record highs? Rick Thoman, climate science and services manager for the NOAA/NWS Alaska Region, relays the history of Barrow/Utqiagvik and its weather observation network below.

RicK Thoman on the history of Utqiaġvik (Barrow) and its weather observations

“Utqiaġvik (Barrow) is the northernmost community in the United States. Located at a latitude of 71°17’ N, it is some 320 miles north of the Arctic Circle. With a population of more than 4000, Utqiaġvik is the seat of government and commerce for the vast North Slope Borough (which is about the same areal size as Oregon). The region has been home to Inupiat peoples for thousands of years. Being less than 10 miles from the northernmost point of land in Alaska (Point Barrow), the area attracted European explorers starting in the early 1800s, followed by commercial whaling interests.

“The original town site sits on a low bluff overlooking the Chukchi Sea to the west, though over time there has been growth onto lower-lying areas to the northeast. Utqiaġvik is one of a large number of Alaska coastal communities that are threatened by increased erosion and coastal flooding, a direct result of recent declines in sea ice extent and duration.

“Weather and climate observations have been made for a long time at Utqiaġvik. Personnel with the U.S. Signal Corps made systematic, detailed observations as part of the First International Polar Year (1881-1883). Schoolteachers served as Weather Bureau cooperative climate observers intermittently between 1901 and 1919, though there are obvious quality problems with some of the data from this period.

“A new era in climate observations began in the autumn of 1920, when a second-order Weather Bureau station opened. Second-order stations differed from the purely cooperative climate stations in typically having more equipment (e.g. wind and pressure), and they often took several detailed observations per day. In late 1942, as part of the effort by the Weather Bureau during World War II to dramatically increase the availability of weather observations, Bureau staff took over the weather and climate observation program, and the era of modern climate data collection began.

“While weather and climate observations have been made at many other locations on the North Slope over the years, no place other than Utqiaġvik has anything like an ongoing, continuous set of daily observations that stretches back more than half a century (see note below). The closest active climate stations with more than 50 years of observations are Kotzebue and Bettles, both more than 300 miles away in completely different climate and ecological zones. As such, the Utqiaġvik climate record provides a unique window into the changes that are reshaping Alaska’s Arctic cultures and environment.

“Because of Utqiaġvik’s unparalleled record, it is tempting to generalize trends to the remainder of the North Slope, but this must be done with caution. Utqiaġvik is located on a peninsula separating the Beaufort Sea to the east and the Chukchi Sea to the west. This peninsula is only eight miles wide at the airport location where weather observations are maintained, and it narrows quickly to the north. As a result, Utqiaġvik has a distinctly more maritime climate than coastal locations either to the east or west, where the geography is more favorable for winds to blow from inland toward the coast. At those locations, temperatures are generally higher in the summer and colder in the winter than in Utqiaġvik.

“Observations have been made at the Wiley Post–Will Rogers Memorial Airport in Utqiaġvik since the 1950s. As far as can be determined, the previous observation sites from 1920 onward were all within about three-quarters of a mile (and probably less) of the airport site. The airport is located on the south edge of the Utqiaġvik urban area and is about a mile east of the Chukchi Sea coast. Prevailing winds are east to northeast most of the year, blowing from an area in which there is practically no urban development.

“An ASOS station (Automated Surface Observing System) commissioned at Barrow in June 1998 is located in almost exactly the same place as the thermometers have been since 1977. In the summer of 2002, a CRN (Climate Reference Network) site was established four miles northeast of the airport. It has been used as a back-up for the airport data when sensors fail there, as was the case this past November 2-4.

“Daily temperature extremes have been based on a midnight to midnight (Alaska Time) climatological day for most of the period of record, eliminating that common confounding factor. [When daily highs and lows are calculated from once-a-day morning readings, they tend to be lower on average; if calculated from evening readings, they tend to be higher.]

“In summary, there is no reason to believe that monthly-scale temperatures have been significantly impacted by instrumentation moves or the growth of the urban area (though systematic differences due to instrument changes are possible).”

Figure 4. An aerial image of Utqiaġvik (Barrow), Alaska, from 2014. As is obvious from the image, the unusual warmth that has occurred in recent years cannot be attributed to a major urban heat island effect. Image credit: Wikimedia Commons.

Just the statistics: How Utqiaġvik (Barrow)has warmed dramatically over the past decade

November marked the 22nd out of the past 23 months in Utqiaġvik with above-average monthly temperatures. Since December 2015, only June 2017 has seen a monthly average below normal (-0.9°F).

Figure 5. Utqiaġvik monthly temperature departure from normal over the past two years (Dec. 2015-Nov. 2017). Note that November 2017, July 2017, and May and October 2016 were all respectively the warmest such months on record (since 1920). Image credit: Rick Thoman, NOAA/NWS Alaska Region.

During the time frame of December 2015-November 2017, a total of 25 daily record highs have been set versus zero (0) daily record lows. In fact, the last time Utqiaġvik set a daily record low was almost a decade ago—on December 21, 2007, when a reading of -42°F was achieved. Given its period of record (POR) of 96 years, Barrow should expect to see an average of 4 daily record highs and 4 daily record lows established each year. So for the period from January 2008 through November 2017, we would expect a total of about 37 daily record highs and 37 daily record lows set if the climate were in perfect equilibrium. In fact, the total number of daily record highs set in this span has been 71, versus (as mentioned) zero daily record lows. Yes: a 71-to-0 ratio over the past ten years!

Figure 6. Number of daily record highs and daily record lows by decade for Utqiaġvik. December 2007 was the last month that a daily record low was observed. Of course, there are still two years left for the final tally during the current decade. Image credit: Rick Thoman, NOAA/NWS Alaska Region.

The year 2016 was the warmest year on record for Utqiaġvik, with an annual average temperature of 18.9°F, +7.1° above the annual normal of 11.8°F. The previous warmest year was 1998 with a 17.0°F average. The last year to average below normal in Barrow was 23 years ago in 1994. This year, 2017, is also well on track to make its way into this list. Thus, eight of the 11 warmest years will have occurred in just the past ten years (since 2007). If December 2017 sees a normal average monthly temperature of -7.8°, then the 2017 annual average temperature will end up at 17.2°, putting it in second place on the list below.

Figure 7. Sea ice extent for the Chukchi and Bering Seas as of November 30, 2017. The extent was less than half of the 1981-2010 normal and a full 24% lower than the previous lowest extent observed during the satellite era. Image credit: Rick Thoman, NOAA/NWS Alaska Region.

It’s not just about Utqiaġvik

The topographic setting of Utqiaġvik means that the weather and climate are strongly influenced by presence (or lack thereof) of sea ice, so it’s not just a coincidence that the sea ice extent in the Chukchi and Bering Seas was at its lowest extent for late November since records for such began in 1978.

As is now well observed, the Arctic region of the world has been warming faster than any other on the planet leading to depletion of polar sea ice and melting permafrost. If there is a canary in the coal mine (so to speak) concerning climate change, we can see it in the climate data from Arctic sites like Utqiaġvik (Barrow).

KUDOS: Thanks to Rick Thoman (NOAA/NWS Alaska Region) for much of the above information and graphics.

Christopher C. BurtWeather Historian

Figure 8. Sea ice melts in July 2016 off the beach of Utqiaġvik (Barrow), Alaska, where a field project called Operation IceBridge was based. Credit: NASA/Kate Ramsayer.

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Christopher C. Burt

Christopher C. Burt is the author of "Extreme Weather; A Guide and Record Book." He studied meteorology at the University of Wisconsin–Madison.

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